Earth anchor for structural towers



E. E. BUECHELE ET AL EARTH ANCHOR FOR STRUCTURAL TOWERS v March l, 1927.l 1,619,651

Filed Dec. 13. *1924 2 sheets-sheet 1 1,619,651 March 1, 1927. E ETBUECHELE ET AL v EARTH ANCHOR FOR STRUCTURAL TOWERS Filed Dec. l5. 19242 Sheets-Sheet 2 Patented Mar. 1, 1927.

UNITED STATES nPAfriia'r OFFICE.

EDWARD E. BUECHELE, 0F WEST' vrEW,` AND SIDNEY A. ivrARfiiIN, 0FBRADEORDWOODS, PENNSYLVANIA.

EARTH ANCHOR FOR STRUCTURAL TOWERS;

Applicationkled December 13, 1924. Serial No. 755,655.

The present invention relates to structural towers of the type used insupporting high tension transmission lines, telegraph or telef phonelines, radio antennae, and for similar purposes, and more particularlyto an earth anchor for such` towers.

It has heretofore been proposed to support each leg of a tower by meansof a stu formed of an angle connected at its lower end to a grillageformed of angles and imbedded in the earth at a considerable dis-` tance`below the ground level, the legs of the tower being connected to theupper ends of the stubs either slightly below or slightly above theground level and the stubs being reinforced intermediate theirV ends totake care of lateral and bending strains.

This method of anchoring tower's'is objectionable because of the greatamount of excavation work required for setting the grillages so farbeneath the ground level. Another objection is that with the increase inthe size and weight of towers the stubs are subjected to such greatbending strains that they are liablev to fail in spite of being reinforced to take care of such strains.

By the present invention we provide an anchor construction in which theweight of the tower is? supported by a base or grillage imbedded only ashort dista-nce below the ground level. A stub extends vdownwardly fromeach grillage in a relatively small hole which may be provided bydrilling. Each stub has anchor means attached to its lower end and thehole islled with crushed stone or rubble to a considerable height abovesuch anchor means andthe remainder of the hole filled with earth andrammed. Each stub extends a slight distance above its grillage and has aleg of the tower attached to its upper end. Any upward pull on thestubs, due, for instance, to' wind pressure on the tower tending tooverturn the saine, causes the anchormeans at the lower ends of thestubs to exert an upward thrust on the crushed rockI or rubble in theholes above the anchor means.` This crushed rock or rubble presseslaterally on the'earth walls of the holes and is thereby effective' to'prevent any upward movement-of the stubs. Of course,

the packed earth filling` the holes above theV rock or rubble alsoassists in resisting the upward pull on the stubs:- Thus'it will begrillages forI protecting the soil beneath them from frost and to acertain extent from rain water or water resulting from .melting snow orice.

The invention is illustrated in the Vaccompanying drawings, wherein:

Figure l is a diagrammatic side elevation of atower having` earthanchors embodying our invention;

Y Figure 2 is a'.hori.zontal section along the lilies Il-e-II of Figs'.3 and 4;

Figure 3' is a side elevation, partly in`sec.

tion, of the anchor shown in Figure 2;

s1. i y j l* igure fl is a view similar to Figure 3 but `taken at rightangles thereto;

Figure 5 is a section through the two.

vertical angle bars of which the stub: is comprised I F igureG is asection on the line VI-Vl of Figure 3, showingthe lower endy portiony ofthe stub on a larger scale;

Figure 7 is a detail view oii- .a larger scale of the lower end portionof the stub;

Fig. 8' is a horizontal section along' the lines VIH-VIH of Figs. 9 andl0, showing a modiiied'form of anchor.

Figures 9 and l() are views of such modified fornisimilar to Figures 3and 4L;

Figure ll is a section through the verticalI l angle' bar which formsthe body of the stub of this modified form of anchor;

Figure l2 is a section on the line. Xl'L-XII of Figure 9 showing thelower end portion of the stub on a. largerscale; A

Figure 13 is a detail side view of thc lower end portion of the stub ona larger scale, andv y v Figure-14; is ay diagrammatic sideelevation ofav towerprovided with earth anchors of thev form Vshown-'in Figures S to1'3 inclusive.

In Figure 1 we have illustrated diagraminatically a structural tower Ahaving legs 2 and diagonals 3. The legs of the tower are connected toearth anchors B which, in accordance with our present invention, willpreferably be constructed as hereinafter specifically described. j

iIn the form of the invention ilhistrated in Figures 2 to 7, inclusive,each earth anchor comprises a laterally extending base or grillage Aadapted to be imbedded a relatively slight distance below the groundline Gr--Gr and a stub 5 extendingr downwardly from the center of thegrillage in a relativelysmall and deep hole 6 which may be provided bydrilling.

The grillage may be formed of a plurality of spaced parallel `beams 7tied together at their ends by angle bars 8. Supported byV the beams andextending transversely and centrally thereof are two spaced parallelchannel beams 9; Y

The stub 5 comprises two angle bars 10 arranged with their j anglesfacing away from each other, as shown more particularly in Figure 5.These bars extend between the channel beams 9 and are secured to saidchannel beams by connecting angles 11 adapted to be riveted or bolted tothe legs of the angle barsV and to the webs of the channel beams. A leg2 of the tower is adapted to be secured to the, upper end of the stub inany appropriate manner, as by having one `of the angle bars-10 extend aslight distance above the adjacent channel beam and riveting the lowerend of the leg to such projecting end.

At its lower end the stub has anchor means attached thereto. This anchormeans may be of any appropriate construction to provide laterallyprojecting shoulders for engagement with the crushed rock or rubble 12which is placed in the hole 6 above the anchor means. As illustrated,however, the anchor means comprises angles 13 which are secured to thelegs of the angle bars`10. Reinforcing angles 14 are placed against thelegs of the angles 13 and rivets 15 are passed through these reinforcingangles, the legs of the angles 13 and the legs of the angle bars 10,thus securing the parts rigidly together'. The angles 13 have horizontalflanges 16 at their upper ends which provide the laterally projectingshoulders referred to.

In order to protect the soil upon which the grillage rests from theaction of frost and water, we provide a protecting cover therefor. Thiscover comprises plates 17 attached at their inner side edges to andVsupported by angles 18 secured to the webs of the channel beams 9. Theplates 17 are supported at their outer side edges andV end "edges upon arectangular frame comprising four channel beams 19 connected at the` 10,thus completing the cover. The channelV beams9 are connected at theirouter ends with angles 211 secured to the channel beams 19 of the frame.

The rectangular frame formed by the channel beams 19 and the coverplates 17, 21 and 23 inclose a chamber 25 on the earth bottom of whichthe grillage rests. ln order u for the frost to ai'ect the groundiiiimedi ately below the beams 7 `it would liaveto penetrate to adistance d below the channel `beams 19 eeual tc the horizontal distances between the beams` and the channel beams 19. lt will thus be seen thatby making the distance great enough the protecting cover` will avoid anylikelihood of the ground .be-4 i neath tliebeanis 7 from being affectedby frost. lt will also be apparent that this protecting cover `provides.a substantial Water-shed for protecting Nthe ground beneath the beamsfrom rain Water or water resulting from melting sncw or ice.

lll)

In setting the anchor in the ground, the

ground will first be excavated to provide a rectangular cavity to placethe grillage lat the desired distance below the ground line G-G. Thehole G will next be formed to the desired depth. The `stub will then beplaced in the hole and the latter filled to the desired height with thecrushed rocla:` j

oi rubble 12. After the rock or rubble is rammed the remainder of theVhole is filled Y with dirt which is compacted in the` hole. The grillagewill V,then be placed 4in the cavity and connected to the upper end `ofthe stub. The grillage may be wholly or partlyassembled at the place oferection asinay be found to be most desirable. After `the anchors for atower have been thusI set in ci the tower coiii nected thereto, thecavities above the gril-` the ground and the legs lages and theirprotecting Vcovers will be.

filled in te the ground line GHG. Y

The modified forni of i anchor shown in Figures 8 lto 13, inclusive, isdesigned for lighter tower constructions, such as shown in lFigure 14,and does not differ essentially from that already described. The stub Bcomprises a single angle bar 26 the legs of cured to the ends oftheangles 27Y and eX- tend at right angles thereto.

The grillage of this modified construction .comprises I-beams 29 andchannel beams` 30.

The protecting cover for the grillage comprises a rectangular framecomposed of channel beams 3l and cover plates 32 and 33 connected to thechannel beams 30 and 3l in appropriate manner.

Vhen a structural tower is to be provided with earth anchors inaccordance with our invention7 the grillages will be designed to sustainthe load due to the weight of the tower and the stubs will be designedto withstand the tension stresses to which they will be subjected due toupward pull on the stubs caused by forces tending to overturn the tower.The grillages which are embodied in the surface soil which is generallynot as compact as the deeper soil, have a considerably greaterkhorizontal area than the anchor means and serve to take the load on thelegs and relieve the stubs of downward thrust or bending strains. Sincethe hole in which the grillage is buried is shallow, it may be easilymade much Wider than the deep hole in which the stub and anchor means isburied. Of course the forces tending to overturn the tower will beresisted to some extent by the weight of the grillages and theirprotecting covers. Any upward pull on the stubs will be resisted mainlyby the crushed rock or rubble in the holes above the anchor means at thelower endsof the stubs. The upward thrust on this crushed rock or rubblefilling will cause the pieces of rock or rubble to be thrust laterallyinto the earth walls of the holes. The holes must therefore be deepenough so that this lateral thrust of the crushed rock will not causethe earth walls of the holes to give way.

While we have shown and described certain preferred embodiments of ourinvention, it will be understood that the invention is not limited tothe details of construction shown and described but that it may beotherwise embodied within the scope of the appended claims.

We claim:

1. A structural tower having a plurality of spaced legs and earthanchors secured thereto. each anchor comprising a stub eX- tendingdownwardly in a hole provided therefor and adapted to withstand thetension stresses to which it may be subjected due to the upward pull onthe stub caused by forces tending to overturn the tower, said stubhaving anchor means at its lower end adapted to cooperate with fillingmaterial placed above said anchor means to transmit forces due to suchupward pull to the surrounding earth and thereby prevent upward movementof the stub, and a laterally extending base at the upper end of the stubfor sustaining the portion of the weight of the tower distributed to theleg and adapted to be secured in place after the anchor means is buried.

2. A structural tower having a plurality of spaced legs and earthanchors secured thereto, each anchor comprising` a stub eX- tendingdownwardly in a hole provided therefor' and adapted to withstand thetension stresses to which it may be subjected due to the upward pull onthe stub caused by forces tending to overturn the tower, said stubhaving anchor means at its lower end adapted to cooperate with fillingmaterial placed above said anchor means to trans* mit forces due to suchupward pull to the surrounding earth and thereby prevent upward movementof the stub, and a laterally extending base at the upper end of the stubfor sustaining' the portion of the weight of the tower distributed tothe leg and adapted to be secured in place after the anchor means isburied, said base having a considerably greater horizontal area than theanchor means.

3. A structural tower having a plurality of spaced legs and earthanchors secured thereto, each anchor comprising a laterally extendingbase adapted to sustain the portion of the weight of the towerdistributed to the leg, and a stub extending downwardly from said baseand adapted to withstand the tension stresses to which it may besubjected due to upward pull on the stub caused by forces tending tooverturn the tower, said stub having anchoring means at its lower endadapted to cooperate with filling material placed above said anchormeans to transmit forces due to such upward pull to the surroundingearth and thereby prevent upward movement of the stub.

4. A structural tower having a plurality of spaced legs and earthanchors secured' thereto, each anchor comprising av laterally extendingbase adapted to sustain the portion of the weight of the towerdistributed to the leg, a stub extending downwardly from said base andadapted to withstand the tension stresses to which it may be subjecteddue to upward pull on the stub caused by the forces tending to overturnthe` tower, said stub having anchoring means at its lower end adapted tocooperate with filling material placed above said anchor means totransmit forces due to such upward pull to the surrounding earth andthereby prevent upward movement of the stub, and a protecting cover forsaid base forming a frost insulating chamber on the bottom of which saidbase rests.

In testimony whereof we have hereunto set our hands.

lEDWARD E. BUECHELE.

SIDNEY A. MARTIN.

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